武汉肉类食品中大肠杆菌O157∶H7分离株stx亚型和毒力特征分析  

stx Genotypes and Virulence Characteristics of E. coli O157:H7 Strains Isolated from Meat Products Commercialized in Wuhan

作　　者：郑冬冬[1] 毕旺来[1] 王宏勋[2] 刘志国[1] 丁洪波[1] 李睿[1,3] 

机构地区：[1]武汉轻工大学生物与制药工程学院,湖北武汉430023 [2]武汉轻工大学食品科学与工程学院,湖北武汉430023 [3]农产品加工湖北省协同创新中心,湖北武汉430023

出　　处：《食品科学》2014年第8期94-98,共5页Food Science

基　　金：国家高技术研究发展计划(863计划)(2012AA101703-3);武汉市科技局国际科技合作计划项目(2013030409020113);武汉轻工大学研究生创新基金项目(2012cx019)

摘　　要：从22家市场销售的117份肉类食品中分离出4株大肠杆菌O157∶H7菌株,经PCR检测这4株菌的stx、hly、eae毒力基因均为阳性。采用聚合酶链式反应(polymerase chain reaction,PCR)法对这4株菌的stx亚型进行鉴定。3株菌同时携带stx1、stx2基因,且均为stx1a、stx2a亚型。菌株EC5.11仅携带stx2基因,但在所有的stx2分型PCR反应中都为阴性。用PCR扩增该菌株stx2基因全长并克隆测序,序列分析结果表明EC5.11志贺毒素基因为stx2c亚型。采用Vero细胞毒性实验检测这4株菌产志贺毒素的状况,结果显示这些菌株都具有一定的Vero细胞毒性。A total of 117 raw meat samples were collected from 22 markets in Wuhan,China and four E.coli O157∶H7 strains were isolated from these meat samples,which were positive for stx,hly and eae genes.The stx variant genes were further subtyped by polymerase chain reaction （PCR） using sequence-specific primers targeting each stx variant.Three isolates were found to carry both stxl and stx2 genes,and the prevalent stx genotypes were stxla and stx2a.One isolate EC 5.11 was found to carry only stx2 gene but it could not be subtyped by PCR assay.The entire stx2 gene was then amplified from EC 5.11,cloned into a vector and sequenced.Sequencing data showed that the stx2 gene of EC5.11 was 100％ identical to the published sequences of stx2c.The production of Shiga toxin from the four isolates was confirmed by Vero cell toxicity assay.

关 键 词：大肠杆菌O157∶H7 志贺毒素 stx亚型 Vero细胞毒性 

分 类 号：R155.5[医药卫生—营养与食品卫生学]